<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta http-equiv="X-UA-Compatible" content="IE=edge">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <title>Document</title>
    <style>
        .big {
            width: 1000px;
            height: 500px;
            display: flex;
            justify-content: center;
            align-items: center;
            border: 2px solid red;
        }
        .content1 {
            width: 10%;
            height: 200px;
            background-color: #f0f0f0;
        }
        .content2 {
            width: 25%;
            height: 300px;
            background-color: #f1f010;
        }
        .content3 {
            width: 25%;
            height: 250px;
            background-color: #4f1;
        }
    </style>
</head>
<body>
    <div class="big">
        <div class="content1"></div>
        <div class="content2"></div>
        <div class="content3"></div>
    </div>
</body>
</html>